Leg loading during quiet standing and sit-to-stand movement for one year after total hip arthroplasty.

BACKGROUND

The objective of the present study was to investigate loading of the operated leg during quiet standing and sit-to-stand (STS) movement for 1 year after total hip arthroplasty (THA).

METHODS

One hundred and fifty-eight patients with end-stage hip osteoarthritis (OA) who had undergone unilateral primary THA participated in this study. The load distribution on the operated and non-operated legs was computed by measuring the vertical reaction force of the operated and non-operated legs during quiet standing and STS movement. We investigated the load distribution using Pressure Distribution Measurement Platform preoperatively and 1, 2, 3, 6, and 12 months postoperatively.

FINDINGS

Loading of the operated leg during quiet standing was restored 1 month postoperatively. Loading of the operated leg during STS movement was higher within 2 months postoperatively than the preoperative levels and continued to increase 1 year postoperatively. Loading of the operated leg was lower during STS movement than that during quiet standing, even 1 year postoperatively.

INTERPRETATION

A longitudinal and dynamic assessment of loading of the operated leg after THA is clinically important, and the loading during STS movement might continue to increase for a year after THA.